Dinuclear and water-soluble rhodium complexes and hydroformylation catalysis therewith

ABSTRACT

Novel dinuclear and water-soluble rhodium complexes, well suited as hydroformylation catalysts, as are aqueous solutions thereof, have the general formula: ##STR1## in which R and R&#39;, which are identical or different, are each a substituted or unsubstituted hydrocarbon radical, with the proviso that R and R&#39; may together form a single divalent radical, TAPS is a sulfonated triarylphosphine ligand, and L is a carbonyl (CO) or a TAPS ligand.

This application is a division of application Ser. No. 788,202 filedOct. 16, 1985, U.S. Pat. No. 4,778,905.

BACKGROUND OF THE INVENTION

1. Field of the Invention:

The present invention relates to dinuclear and water-soluble rhodiumcomplexes, and to the use of such complexes or aqueous solutions thereofas hydroformylation catalysts.

2. Description of the Prior Art:

Dinuclear rhodium complexes of the type (1): ##STR2## and their use as ahydroformylation catalyst are described in U. S. Pat. No. 3,501,581.However, these catalysts have low activity.

Dinuclear rhodium complexes of the type (2): ##STR3## (in which t-Budenotes a tert-butyl radical) or of the type (3): ##STR4## denotes aresidue derived from chloromethylated polystyrene: ##STR5## and theiruse as hydroformylation catalysts are described in U.S. Pat. No.4,215,066.

However, while the fundamental interest in these rhodium complexes isnot in doubt, the development of their use as catalysts on an industrialscale is hindered by their lack of selectivity. In fact, the ratio n/n+iso (n: normal linear aldehyde; iso: branched aldehyde) which complexesof this type provide in hydroformylation reactions is notoriouslyinadequate, which severely burdens the overall economics of thisprocess.

Furthermore, the recovery and the recycling of the complexes of the type(2) are complicated by difficulties traditionally associated withhomogeneous catalysis reactions, difficulties whose severity is furtherincreased by the fact that the loss of even the smallest quantity ofrhodium is economically prohibitive.

It might have been thought possible to remedy these disadvantages, atleast insofar as the catalyst recovery and recycling are concerned, byusing complexes of the type (3) above, namely, compounds in which theorganometallic complexes are "immobilized" on a solid organic (ormineral) support through the intermediacy of functional groups in thesaid support. It is generally observed, however, that a significant partof the metal goes into solution in the liquid reaction phase (see,particularly W. H. Lang et al, J. Organomet. Chem., 134, 85 (1977)).

In addition, as taught by J. Falbe in New Synthesis with CarbonMonoxide, Springer Verlag (1980), the catalyst solids thus obtained aremuch more sensitive to deactivation and poisoning than similar solublecatalysts.

It will be seen, therefore, that the merit of such "supported complexes"cannot be established industrially, all the more so since their useinvolves difficulties in connection with mass and/or heat transfers.

SUMMARY OF THE INVENTION

Accordingly, a major object of the present invention is the provision ofnovel dinuclear and water-soluble rhodium catalyst complexes; the use ofsuch complexes and/or aqueous solutions thereof to catalyze thehydroformylation of olefins avoids those disadvantages and drawbacks todate characterizing the state of this art.

The novel rhodium complexes according to this invention not only make itpossible to attain high n/n + iso ratios upon use thereof ashydroformylation catalysts, with an activity which is slightly superiorto that obtained (all conditions being otherwise equal) when using amononuclear complex, but also permit easy separation of the variousend-products of the reaction.

Indeed, the facts that the reactants and the reaction products arepresent in an organic liquid phase and/or in a gaseous phase, and thatthe catalyst system can be found wholly (or virtually wholly) in anaqueous liquid phase, enable the separation thereof simply by stoppingthe stirring of the reaction mixture and, where applicable, by releasingthe pressure; the use of completely liquid phases promotes mass and heattransfers.

Briefly, the present invention features dinuclear and water-solublerhodium complexes having the general formula (I): ##STR6## in which Rand R', which are identical or different, are each a hydrocarbon or asubstituted such hydrocarbon radical bearing one or more substituentswhich do not interfere with the intended uses of the complexes inquestion, with the proviso that R and R' may together form a singledivalent radical; TAPS is a sulfonated triarylphosphine ligand; and L isa carbonyl (CO) ligand or a TAPS ligand. This invention also featuresthe use of these complexes or of the aqueous solutions thereof tocatalyze the hydroformylation of unsaturated compounds.

DETAILED DESCRIPTION OF THE INVENTION

More particularly according to the present invention, the sulfonatedtriarylphosphine ligands which are particularly suitable are representedby the formula (II): ##STR7## in which Ar₁, Ar₂ and Ar₃, which areidentical or different, are each carbocyclic aryl groups; Y₁, Y₂ and Y₃,which are identical or different, are each a straight or branched chainalkyl radical containing from 1 to 4 carbon atoms, an alkoxy radicalcontaining from 1 to 4 carbon atoms, a halogen atom a hydroxyl group, anitrile group, a nitro group or a disubstituted amino group of theformula --NR₁ R₂ wherein R₁ and R₂, which are identical or different,are each a straight or branched chain alkyl radical containing at most 4carbon atoms; M is a cationic residue of inorganic or organic origin,selected from among hydrogen and the inorganic cations derived fromalkali metals or alkaline earth metals, or derived from lead, zinc orcopper, the ammonium cation (NH₄ ⁺), and quaternary ammonium cations;m₁, m₂ and m₃ are identical or different integers ranging from zero to5; and n₁, n₂ and n₃ are identical or different integers ranging fromzero to 3, with at least one of said integers n₁ to n₃ being greaterthan or equal to 1.

The aforesaid ligands are known compounds, described especially inFrench Pat. No. 2,314,910 and Patent of Addition thereto, No. 2,349,562.

The preferred TAPS ligands correspond to the formula (II) above, inwhich:

(i) Ar₁, Ar₂ and Ar₃ are phenyl groups;

(ii) Y₁, Y₂ and Y₃, which are identical or different, are each alkylradicals containing from 1 to 2 carbon atoms, alkoxy radicals containingfrom 1 to 2 carbon atoms or chlorine atoms;

(iii) M is a cation selected from among the hydrogen cation, theammonium cation, the cations derived from sodium, potassium, calcium andbarium, and the quaternary ammonium cations of formula N(R₃ R₄ R₅ R₆) inwhich R₃, R₄, R₅ and R₆, which are identical or different, are eachstraight or branched chain alkyl radicals containing at most 4 carbonatoms; and

(iv) m₁, m₂ and m₃ are integers ranging from 0 to 3, inclusive.

The TAPS ligands which are most particularly preferred correspond to theformula (II) above, in which:

Ar₁, Ar₂ and Ar₃ are phenyl groups;

m₁, m₂ and m₃ are zero;

M is selected from among the cations derived from sodium, potassium,calcium, barium, the ammonium cation and the tetramethyl and tetraethylammonium cations; and

the SO₃ group(s) is (are) in the meta position.

As other examples of suitable TAPS ligands, representative are thealkali metal or alkaline earth metal salts, ammonium salts, and thequaternary ammonium salts of the following sulfonated phosphines:

(m-sulfophenyl)diphenylphosphine,

(p-sulfophenyl)diphenylphosphine,

(m-sulfo-p-methylphenyl)di(p-methylphenyl)phosphine,

(m-sulfo-p-methoxyphenyl)di(p-methoxyphenyl)phosphine,

(m-sulfo-p-chlorophenyl)di(p-chlorophenyl)phosphine,

di(m-sulfophenyl)phenylphosphine,

di(p-sulfophenyl)phenylphosphine,

di(m-sulfo-p-methylphenyl)(p-methylphenyl)phosphine,

di(m-sulfo-p-methoxyphenyl)(p-methoxyphenyl)phosphine,

di(m-sulfo-p-chlorophenyl)(p-chlorophenyl)phosphine,

tri(m-sulfophenyl)phosphine,

tri(p-sulfophenyl)phosphine,

tri(m-sulfo-p-methylphenyl)phosphine,

tri(m-sulfo-p-methoxyphenyl)phosphine,

tri(m-sulfo-p-chlorophenyl)phosphine,

(o-sulfo-p-methylphenyl)(m-sulfo-p-methylphenyl-(m,m'-disulfo-p-methylphenyl)phosphine,

(m-sulfophenyl)(m-sulfo-p-chlorophenyl)(m,m'-di-sulfo-p-chlorophenyl)phosphine.

Of course, mixtures of these phosphines may also be used In particular,a mixture of (m-sulfophenyl)diphenylphosphine,di(m-sulfophenyl)phenylphosphine and tri(m-sulfophenyl)phosphine may beemployed.

The dinuclear and water-soluble rhodium complexes according to thepresent invention incorporate two mu-thiolato bridges denoted by --SRand --SR' in the general formula (I), R and R' being as above-defined.

More precisely, R and R', which are identical or different, are each analkyl, aryl, arylalkyl or alkylaryl radical containing at most 12 carbonatoms, or substituted such radicals bearing one or more substituentsselected from among halogen atoms, sulfonate, carboxylate, cyano anddisubstituted amino groups of formula --NR₁ R₂, in which R₁ and R₂ areas above defined, ammonium and phosphonium groups, and alkoxy radicalscontaining from 1 to 4 carbon atoms, with the proviso that R and R' maytogether form a single, straight or branched chain divalent alkylene,alkenylene, or alkadienylene radical containing from 3 to 6 carbonatoms.

R and R' are preferably identical. They are furthermore advantageouslyselected from among alkyl radicals containing at most 4 carbon atoms andthe benzyl radical; R and R' are advantageously a tert-butyl radical.

The dinuclear and water-soluble rhodium complexes according to thepresent invention also incorporate one ligand L per rhodium atom. L isadvantageously a carbonyl ligand.

The complexes of the invention may be prepared by methods which areknown per se from dinuclear rhodium complexes containing a mu-chlorobridge, such as di-mu-chlorotetracarbonyldirhodium(I), itself preparedas described in Inorganic Syntheses, 8, page 211 (1968).

To effect this, di-mu-chlorotetracarbonyldirhodium(I) is reacted eitherwith thiol(s) of formula(e) HSR (and HSR') or with (a) (for example)lithium thiolate(s), to produce a complex of a related structurecontaining mu-thiolato bridges, which is then in turn reacted with theTAPS ligand to finally prepare the required complex.

The reactions in question may be represented as follows:

    [Rh(mu-Cl)(CO).sub.2 ].sub.2 +2HRS→[Rh(mu-SR)(CO).sub.2 ].sub.2 +2HCl(1)

    [Rh(mu-Cl)(CO).sub.2 ].sub.2 +2LiSR→[Rh(mu-SR)(CO).sub.2 ].sub.2 +2LiCl                                                    (2)

    [Rh(mu-SR)(CO).sub.2 ].sub.2 +2TAPS→[Rh(mu-SR)(CO)(TAPS)].sub.2 +2CO(3)

in which R and TAPS are as defined above. It is also possible to startwith di-mu-chlorobis(1,5-cyclooctadiene)dirhodium (I) [RhClCOD)]₂ toform, in a similar manner, the complex [Rh(mu-SR)(COD)]₂, which is thenreacted with the TAPS ligand in accordance with the reaction (4) below:

    [Rh(mu-SR)(COD)].sub.2 +4TAPS→[Rh(mu-SR)(TAPS).sub.2 ].sub.2 +2COD(4)

Naturally, when R and R' are different, use will be made of the twocorresponding thiols (or thiolates).

It will be appreciated that when the thiols employed in reaction (1) arecommercial products, the ligands TAPS are known products which can beprepared using processes which are also known. Thus, in accordance withthe teaching of H. Schindlbauer, Monatsh. Chem., 96, pages 2051-2057(1965), the sodium salt of (p-sulfophenyl)diphenylphosphine may beprepared by reacting sodium p-chlorobenzenesulfonate withdiphenylchlorophosphine in the presence of sodium or potassium.According to the method described in J. Chem. Soc., pages 276-288 (1958)and in British Pat. No. 1,066,261, phenylphosphines of formula (II) canbe prepared by sulfonation of aromatic nuclei by means of oleum, andthen neutralizing the sulfonic groups formed by means of a suitablebasic derivative of one of the metals denoted by M in the formula (II).The crude sulfonated phosphine obtained may contain an admixture of thecorresponding sulfonated phosphine oxide, the presence of which,however, though undesirable, does not interfere with the intended use.

Assuming that it is intended to use tri(m-sulfophenyl)phosphine ofimproved quality, that is to say, containing as little oxides aspossible [phosphorus oxidation state V (P^(V))], it will be whollyadvantageous to prepare it according to the method described inpublished French Patent Application No. 82/14,862.

In one embodiment thereof, the present invention relates to the use ofthe dinuclear and water-soluble rhodium complexes of formula (I) ascatalysts or precursors of metal species which are catalytically activein the hydroformylation of organic compounds containing at least onecarbon-carbon double bond.

In another embodiment the present invention relates to the use of therhodium complexes in question as catalysts or precursors of metalspecies which are catalytically active in the hydroformylation oforganic compounds containing at least one carbon-carbon double bond, inthe form of their aqueous solutions.

The hydroformylation of organic compounds containing at least onecarbon-carbon double bond is carried out in liquid phase with a view toproducing aldehyde compounds and comprises contacting at least onecompound containing a carbon-carbon double bond with carbon monoxide andhydrogen in the presence of an aqueous solution of a dinuclear rhodiumcomplex of formula (I) above and, where appropriate, a sulfonatedphosphine of formula (II) above.

The organic compounds containing at least one carbon-carbon double bondwhich are capable of being hydroformylated consistent herewith includealiphatic monoethylenic compounds containing from 2 to 20 carbon atoms,including straight or branched chain olefins containing a terminal orinternal double bond, conjugated dienes incorporating the 1,3-butadienestructure in their molecule, and styrene.

By way of examples, the following are representative: among theethylenic hydrocarbons: ethylene, propylene, 1-butene,2-methyl-1-butene, 2-butene, 1-pentene, 2-pentene, 1-hexene,3-ethyl-1-hexene, 2-propyl-1-hexene, 2-hexene, 1-heptene, 1-octene,3-octene, 4,4-dimethyl-1-nonene, 1-decene, 2-decene, 6-propyl-1-decene,3-undecene, 1-dodecene, 5-tetradecene, 1-octadecene, 2-octadecene; amongthe conjugated dienes containing the 1,3-butadiene structure in theirmolecules: 1,3-butadiene, isoprene, piperylene, 1,3-hexadiene,2,4-hexadiene, chloroprene, 1-cyclohexyl-1,3-butadiene,1-phenyl-1,3-butadiene, 2,4-octadiene, 3-methyl-1,3-pentadiene,2-methyl-2,4-pentadiene, 1,3-cyclohexadiene, 1,3-cyclooctadiene,optionally substituted by the alkoxycarbonyl group, such as methyl2,4-pentadienoate.

The hydroformylation process according to the present invention is mostparticularly applicable to the straight-chain aliphatic monoethyleniccompounds containing from 2 to 8 carbon atoms, such as ethylene,propylene, 1-butene, 1-pentene, 1 -hexene, 2-hexene and 1-octene.

The quantity of rhodium complex generally ranges from 0.0001 to 0.25 andpreferably from 0.0005 to 0.05 mole per liter of reaction solution.

In an advantageously alternative embodiment, the aqueous solutioncontains a sulfonated phosphine in addition to the dinuclear rhodiumcomplex.

With respect to the sulfonated phosphine, the aqueous solution of whichis employed for the hydroformylation process, reference is made to theabove description on the subject of the sulfonated triarylphosphinesemployed as a ligand in the dinuclear and water-soluble rhodiumcomplexes of formula (I).

In fact, while the actual nature of the sulfonated phosphines may vary,depending on whether they are employed as a ligand in the complexes inquestion or in the form of their aqueous solutions for thehydroformylation process, their general definition remains unaltered,and the same sulfonated phosphine or the same mixture of sulfonatedphosphines will advantageously be employed to prepare the rhodiumcomplexes of formula (I) extemporaneously and to carry out thehydroformylation process. In the latter case the in situ synthesis ofthe complex of formula (I) may even be envisaged, under the conditionsof hydroformylation, from the sulfonated phosphine in question and acompound [Rh(mu-SR)(CO)₂ ]₂ (precursor), mentioned earlier (cf. reaction3), or it may even be possible to form this precursor in situ from thecomplex of a related structure containing mu-chloro bridges and asuitable thiol (or thiolate) (cf. reactions 1 and 2).

The quantity of sulfonated phosphine of formula (II) which is employedto prepare the reaction solution is selected such that the atomic ratioof phosphorus in the oxidation state III to rhodium, P^(III) /Rh, rangesfrom 1 to 300 and, preferably, from 1.5 to 100.

Although the reaction is preferably carried out in water, it may beadvantageous to use an inert organic solvent, and especially awater-miscible solvent, preferably having a boiling point below that ofwater, and employed in a quantity such that it makes it possible toincrease, if need be, the solubility of the olefin in the aqueouscatalyst solution, without, however, rendering the formed aldehydeproducts miscible in the aqueous phase. The solvents which can be thusemployed include saturated, straight or branched chain aliphaticmonohydroxylated compounds such as methyl alcohol, ethyl alcohol, propylalcohol and isopropyl alcohol; saturated aliphatic ketones such asacetone, lower aliphatic nitriles such as acetonitrile, and diethyleneglycol methyl ether and dimethoxyethane.

It is also possible to us a water-immiscible solvent such as benzene,toluene, benzonitrile, acetophenone, ethyl ether, propyl ether,isopropyl ether, octane, methyl ethyl ketone and propionitrile.

The temperature at which the reaction is carried out can vary over widelimits. More particularly, it is carried out at moderately elevatedtemperatures which may vary from 20° C. to 50° C., and preferably from50° C. to 120° C.

The value of the total pressure of hydrogen and of carbon monoxide whichis required for using the process may be that of atmospheric pressure,although higher pressures are preferred; total pressures of from 1 to200 bars and preferably from 10 to 100 bars will generally be suitable.

The partial pressures of carbon monoxide and of hydrogen in the gasmixture employed are such that the molar ratio carbon monoxide/hydrogenvaries from 0.1 to 10; preferably, a molar ratio which varies from 0.2to 5 is employed.

A practical method of using the process of the invention consists ofcharging into a pressure-resistant reactor, purged beforehand with aninert gas (nitrogen or argon), either the preformed aqueous catalystsolution or the various components: a dinuclear and water-solublerhodium complex of formula (I) or a precursor specified above, water,where appropriate, the sulfonated phosphine in aqueous solution and,when found to be desirable, the organic solvent. The organic compoundcontaining at least one carbon-carbon double bond is then charged. Thereactor is then heated to the reaction temperature before or after theaddition of carbon monoxide and hydrogen which, for their part, may beadded simultaneously or separately, before or after, or at the same timeas the unsaturated compound.

When the reaction has ceased, the mixture is cooled to ambienttemperature in the region of 20° C. and the excess gas present isreleased. The reactor contents are then withdrawn and it then sufficesto isolate the aldehyde products by carrying out a phase separation and,if appropriate, a washing with a suitable solvent such as, for example,diethyl ether, benzene or toluene. It is also possible to separate thealdehyde products from the residual mixture, after filtration if needbe, by extraction with one of the above-mentioned solvents. Althoughphase separation and extraction are the preferred methods of treatment,it is also possible to use the distillation technique to isolate thealdehyde products formed.

The residual aqueous solution may be recycled into the reactor tocatalyze a new hydroformylation operation. The process according to theinvention is particularly suitable for continuous operation.

In order to further illustrate the present invention and the advantagesthereof, the following specific examples are given, it being understoodthat same are intended only as illustrative and in nowise limitative.

EXAMPLES Examples of Complexes According to the Invention EXAMPLE 1

This example illustrates the preparation of a complex according to theinvention, incorporating two mu-tert-butylthiolato bridges and twotri(m-sulfophenyl)phosphine ligands in the form of its sodium salt(TPPTS)

(a) Synthesis of [Rh(mu-S-t-Bu)(CO)₂ ]₂ :

A slight excess (2.2 10⁻³ mole) of lithium tert-butylthiolate (obtainedby the reaction of n-butyl lithium with t-butylthiol) in 10 ml oftoluene was added to 0.390 g (10⁻³ mole) ofdi-mu-chlorotetracarbonyldirhodium (I) dissolved in 20 ml of toluene.The solution immediately turned a luminous yellow while a fine whiteprecipitate appeared. After 15 minutes of reaction, the toluene wasdistilled off under reduced pressure and the compound was extractedthree times with 10 ml portions of hexane and was separated by filteringoff the lithium chloride.

The yield was quantitative.

(b) Synthesis of the complex [Rh(mu-S-t-Bu)(CO)(TPPTS)]₂ :

To a solution of 0.496 g (10⁻³ mole) ofdi-(mu-tert-butylthiolato)tetracarbonyldirhodium (I), obtained in (a),in 30 ml of methanol, was added 1.23 g of TPPTS titrating at 1.63 10⁻³equivalent of phosphorus in oxidation state (3) per gram (i.e., 2 10⁻³equivalent of P^(III)) and containing di(m-sulfophenyl)phenyl phosphinein the form of its sodium salt [the molar ratio oftri(m-sulfophenyl)phosphine to di(m-sulfophenyl)phenylphosphine was62/27].

Gas evolution took place and the solution became more markedly yellow.It was maintained stirred until all the phosphine had been consumed, andthe solvent was then distilled off under reduced pressure. The compoundobtained was bright yellow. The yield was quantitative.

Analysis of a solution of the said compound in methanol by infraredspectroscopy showed the presence of a stretching vibration of thecarbonyl group, a band of very high intensity at 1967 cm⁻¹ and a band ofhigh intensity at 1955 cm⁻¹ being observed. Analysis by ³¹ P nuclearmagnetic resonance showed the presence of a doublet at 36.5 ppm with aRh-P coupling constant of 152 Hz.

This complex will be referred to below as "complex 1".

EXAMPLE 2

This example illustrates the preparation of a complex according to theinvention containing two mu-phenylthiolato bridges and two TPPTSligands.

(a) Synthesis of [Rh(mu-S-Ph)(CO)₂ ]₂ (Ph=phenyl):

0.206 ml (2 10⁻³ mole of thiophenol) was added slowly under acountercurrent stream of nitrogen to 0.390 g (10⁻³ mole) ofdi-mu-chlorotetracarbonyldirhodium (I) in 20 ml of hexane. The yellowsolution became colored red instantaneously and bright red plateletsprecipitated gradually. After 30 minutes of reaction, the yellowsolution was separated off by filtration and the compound obtained wasdried under vacuum.

The yield was quantitative.

(b) Synthesis of the complex [Rh(mu-S-Ph)(CO)(TPPTS)]₂

(Ph=phenyl):

1.23 g of TPPTS, the properties of which were indicated earlier,dissolved in 10 ml of water, was added to 0.536 g (10⁻³ mole) ofdi(mu-phenylthiolato)tetracarbonyldirhodium (I) obtained in (a),suspended in 20 ml of methanol. The solution became brown-yellow incolor gradually, while gas evolution took place. It was maintainedstirred until complete dissolution and then, once the solution washomogeneous, the solvent was distilled off under reduced pressure. Theyield was quantitative.

Analysis of a dispersion of the said complex in cesium bromide byinfrared spectroscopy showed the presence of a broad band of very highintensity at 1980 cm⁻¹.

This complex will be referred to below as "complex 2".

EXAMPLE 3

The complex: [Rh(mu-S-CH₃)(CO)(TPPTS)]₂ was prepared in a similar mannerfrom di(mu-methylthiolato)tetracarbonyldirhodium (5) and TPPTS, theproperties of which were indicated in Example 1 above.

Analysis of a dispersion of the said complex in Nujol by infraredspectroscopy showed the presence of a broad band of very high intensityat 1970 cm⁻¹.

This complex will be referred to below as "complex 3".

EXAMPLE 4

The complex: [Rh(mu-S-CH₂ -Ph)(CO)(TPPTS)]₂ was prepared in a similarmanner from di(mu-benzylthiolato)tetracarbonyldirhodium (I) and TPPTS,the properties of which were indicated in Example 1 above.

Analysis of a dispersion of the said complex in potassium bromide byinfrared spectroscopy showed the presence of a broad band of very highintensity at 1962 cm⁻¹.

This complex will be referred to below as "complex 4".

EXAMPLE 5

The complex: [Rh(mu-S-C₆ F₅)(CO)(TPPTS)]₂ was prepared in a similarmanner from di [mu-(pentafluorophenyl)thiolato]tetracarbonyldirhodium(I) and TPPTS, the properties of which were indicated in Example 1above.

This complex will be referred to below as "complex 5".

EXAMPLE 6

The complex having the formula: ##STR8## was prepared in a similarmanner in two steps from di(mu-chloro)tetracarbonylrhodium (I) which wasreacted in a first step with 1,2-ethanedithiol to form the complex:##STR9## which was then reacted, in a second step, with TPPTS. The yieldwas quantitative.

Analysis of a dispersion of the said complex in Nujol by infraredspectroscopy showed the presence of a broad band of very high intensityat 1996 cm⁻¹.

This complex will be referred to below as "complex 6".

Examples of Use of Complexes According to the Invention inHydroformylation Reactions Operating procedure in the case of gaseousorganic reactants under normal temperature and pressure conditions(e.g.: propylene, butadiene, etc.)

Tri(m-sulfophenyl)phosphine in the form of its sodium salt and therhodium compound were added in the required quantities to distilled anddeaerated water (20 ml). The catalyst solution was then transferred bysiphoning under argon to a 125 cm³ stainless steel autoclave. Therequired quantity of gaseous organic reactant was then transferred intothe autoclave by means of a lock chamber. The autoclave was thenpressurized with a gas mixture consisting of CO and H₂ in the requiredratio by volume, and was then closed. The total pressure applied atambient temperature was such that after the temperature had been raisedthe total pressure obtained was slightly below the required totalpressure. Agitation of the reaction mixture was effected by shaking.When the required temperature had been reached, the autoclave wassupplied at constant pressure from a reserve vessel containing the gasmixture (CO and H₂ in a volume ratio of 1). After a given reaction timethe autoclave was returned to ambient temperature and the pressure wasslowly released. The reaction mixture was then transferred, under argon,to a separating funnel by siphoning. It separated into two phases. Theorganic phase was analyzed by gas phase chromatography. The aqueousphase containing the catalyst system may be recycled if appropriate.

Operating procedure in the case of liquid organic reactants under normaltemperature and pressure conditions

The only difference was in the method of addition of the reactant. Thelatter was added into the reactor in the same manner and at the sametime as the aqueous catalyst phase. (The use of a lock chamber was nolonger necessary.)

The conventions employed in the examples below are the following:

L=denotes the degree of linearity in the aldehydes produced, defined asbeing the ratio n/(n+iso). It is expressed in percent.

Pr=denotes the volume production rate expressed in grams of n-aldehydeobtained per hour and per liter of aqueous catalyst solution.

M(org.ph)=denotes the mass of the organic phase obtained after phaseseparation, expressed in grams.

RY=number of moles of linear aldehyde formed relative to the number ofmoles of the substrate used.

ND=not determinable.

EXAMPLES 7 to 24

A series of hydroformylation tests was carried out using propylene, witha CO/H₂ ratio of 1/1 (by volume) at 120° C., under a pressure ofapproximately 50 bars at reaction temperature, in the presence of TPPTSthe properties of which were indicated in Example 1, in the case ofExamples 7 to 20, the TPPTS having the following properties in Examples21 to 24: it was in the form of an aqueous solution containing 0.59mole/liter of P ^(III) at 97 mol percent of tri(m-sulfophenyl)phosphinein the form of its sodium salt and in the presence of 0.097 10⁻³gram-atom (g-at) of rhodium, employed in the form of a complex, theprecise nature of which is indicated in Table I below, each exampleincorporating the word "recycle" being carried out by recycling theaqueous catalyst phase recovered by phase separation at the end of theimmediately preceding test.

Thus, Example 10 was carried out using, as catalyst solution, theaqueous phase collected upon completion of the test described in Example9.

The results obtained, and the particular conditions, are reported inTable I below.

Examples 7, 8, 11 and 12, carried out with the dimer ofchloro-1,5-cyclooctadienerhodium [(RhCl(COD)]₂, which are not within thescope of the present invention, are given by way of comparison.

                  TABLE I                                                         ______________________________________                                             Propy-                                                                        lene                          M                                          EX.  10.sup.-3                                                                             Nature of   P/   Time (org.                                      No.  Mol     catalyst    Rh   in hr                                                                              ph)   Pr   L                               ______________________________________                                         7   190     [RhCl(COD)].sub.2                                                                         100  2    1.6    36  95                               8   "       recycle     "    2.3  2.5    48  96                               9   202     complex 1   "    1.5  4.1   136  96                              10   190     recycle     "    "    4.0   127  95                              11   167     [RhCl(COD)].sub.2                                                                         50   1    1.1    50  92                              12   178     recycle     "    "    2.9   130  92                              13   190     complex 1   "    "    5.5   278  96                              14   "       recycle     "    "    11.1  384  93                              15   "       recycle     "    "    8.5   364  92                              16   179     complex 4   "    "    6.3   281  92                              17   428     recycle     "    2.9  21.8  330  93                              18   190     recycle     "    1    7.6   335  92                              19   "       complex 2   "    "    traces                                                                              ND   ND                              20   "       recycle     "    "    6.4   182  93                              21   "       complex 3   "    "    7.1   303  93                              22   179     recycle     "    "    11.7  522  93                              23   428     complex 6   "    "    4.3   190  95                              24   190     complex 5   "    "    6.0   180  93                              25   288     complex 1   10   "    10.1  527  95                              26   250     recycle     "    "    14.9  588  94                              ______________________________________                                    

EXAMPLES 27 to 31

A second series of tests was carried out by using the complex 1, thepreparation of which was described in Example 1, in hydroformylationreactions carried out using substrates of various kinds, specified inTable II below, with a CO/H₂ mixture in a volume ratio of 1 in thepresence of TPPTS, the properties of which were given in Example 1, themolar ratio P/Rh being 10, the pressure, measured at reactiontemperature (indicated by T in Table II) being 50 bars. The resultsobtained and the individual conditions are reported in Table II below.

In Example 28, methyl octanal (39 mol percent relative to the productused) and ethyl heptanal (24%) were obtained in addition to the linearaldehyde (nonanal).

In Example 31, 2-phenylpropanal (62%) was obtained in addition to3-phenylpropanal.

EXAMPLES 32 to 35

A third series of tests was carried out by using this same complex 1 in1-hexenehydroformylation. The catalyst solution containing 0.194 10⁻³g-at of rhodium 1.94 10⁻³ mole of tri(m-sulfophenyl)phosphine in theform of its sodium salt and the properties of which were indicated inExample 1, (P/Rh=10) and 2 ml of methanol, the temperature being 120°C., the total pressure at reaction temperature and the H₂ /CO volumeratio being both varied. The results obtained and the individualconditions are reported in Table III below.

                  TABLE II                                                        ______________________________________                                        SUBSTRATE                                                                     Ex.             10.sup.-3                                                                            Rh   T    Time M                                       No.  Nature     Mol    (*)  (°C.)                                                                       in hr                                                                              (org. ph)                                                                            RY                               ______________________________________                                        27   1-hexene   80     0.194                                                                              120  1    6.4    26.3                             28   2-octene   19     0.388                                                                              150  16   2.4    11                               29   1,3-butadiene                                                                            130    0.194                                                                               80  2    5.3    35.3                             30   isoprene   50     "    120  2    1.8    23.4                             31   styrene    44     "    120  1    5.1    15                               ______________________________________                                         (*): 10.sup.-3 gat                                                       

                  TABLE III                                                       ______________________________________                                        Ex.  Pressure  H.sub.2 /CO                                                                            Time                                                  No.  (bar)     (vol.)   in hr M (org. ph)                                                                            RY    E                                ______________________________________                                        32   50        0.4      2     3.2      51    84                               33   80        2        2.2   4.4      63    87                               34   50        2.5      2     3.6      65    92                               35   95        0.5      2     3.2      42    82                               ______________________________________                                    

While this invention has been described in terms of various preferredembodiments, the skilled artisan will appreciate that variousmodifications, substitutions, omissions, and changes may be made withoutdeparting from the spirit thereof. Accordingly, it is intended that thescope of the present invention be limited solely by the scope of thefollowing claims, including equivalents thereof.

What is claimed is:
 1. A hydroformylation catalyst comprising an aqueoussolution comprising a dinuclear and water-soluble rhodium complex havingthe general formula (I): ##STR10## in which R and R', which areidentical or different, are each a hydrocarbon radical or a substitutedsuch hydrocarbon radical bearing one or more inert substituents, withthe proviso that R and R' may together form a single divalenthydrocarbon radical; TAPS is a sulfonated triarylphosphine ligand; and Lis a carbonyl (CO) ligand or a TAPS ligand.
 2. In a process for thehydroformylation of ethylenically unsaturated organic compounds,including aliphatic monoethylenic compounds containing from 2 to 20carbon atoms, including straight or branched chain olefins containing aterminal or internal double bond, conjugated dienes incorporating the1,3-butadiene structure in their molecule, and styrene, which arecontacted with carbon monoxide and hydrogen in the presence of acatalytically effective amount of a hydroformylation catalyst in orderto produce aldehyde compounds, the improvement which comprises utilizingas the catalyst therefor, a dinuclear and water-soluble rodium complexhaving the general formula (I): ##STR11## in which R and R', which areidentical or different, are each a hydrocarbon radical or a substitutedsuch hydrocarbon radical bearing one or more inert substituents, withthe proviso that R and R' may together form a single divalenthydrocarbon radical; TAPS is a sulfonated triarylphosphine ligand; and Lis a carbonyl (CO) ligand or a TAPS ligand.
 3. In a process for thehydroformylation of ethylenically unsaturated organic compounds,including aliphatic monoethylenic compounds containing from 2 to 20carbon atoms, including straight or branched chain olefins containing aterminal or internal double bond, conjugated dienes incorporating the1,3-butadiene structure in their molecule, and styrene, which arecontacted with carbon monoxide and hydrogen in the presence of acatalytically effective amount of a hydroformylation catalyst in orderto produce aldehyde compounds, the improvement which comprises utilizingas the catalyst therefor, the aqueous solution comprising a dinuclearand water-soluble rodium complex having the general formula (I):##STR12## in which R and R', which are identical or different, are eacha hydrocarbon radical or a substituted such hydrocarbon radical bearingone or more inert substituents, with the proviso that R and R' maytogether form a single divalent hydrocarbon radical; TAPS is asulfonated triarylphosphine ligand; and L is a carbonyl (CO) ligand or aTAPS ligand.